Impulse generator



y 1947- J. D. SCHANTZ 2,423,999

' IMPULSE GENERATOR Filed Oct. 1a, 1943 FIG.| l5 I6 a F DELAY 2e 29 14 E; NETWORK fil -J 26 24 |8 I Ml'l'l'l'l'l' gt- 3; \GAS FILLED 25 5= A OUTPUT TEIUGLGSEER |2 Y 27 r; GENERATOR A y 1/ f F162 GAs FILLED 26 """\37 5 DELAY TRIGGER NETWORK PULSE 2| 34 GENERAToR 3 q: E: s l5 la n OUTPUT f DELAY. I 4

NETWORK 2- 24 FIG.3

i vENToR JOSEPH o. SCHANTZ ATTORNEY Patented July 15, 1947 IMPULSE GENERATOR.

Joseph D. Schantz, Fort Wayne, Ind., a'ssignor to Farnsworth Television and Radio Corporation, a corporation of Delaware Application October 18, 1943, Serial No. 506,673

15 Claims. 1

This invention relates to impulse generators and particularly to relatively high frequency generators of this character.

According to conventional practice, impulse generators frequently comprise one or more electronic devices having trigger operating characteristics. By this term is meant the facility of the device to initiate and terminate substantially instantaneously the flow of current therethrough. In one well known device of this character one or more gaseous discharge devices are employed. These devices are fired, or discharges therein are initiated, under the control of a series of triggering impulses derived from some form of timing apparatus. It is characteristic of this type of tube that, so long as a. predetermined anode-to-cathode potential is maintained, the discharge initiating grid loses its control of the discharge once it has been initiated.

Numerous expedients have been utilized to exting'uish the discharge. in the tube at the desired time. One of these has been the employment of a delay network connected to the anode of the discharge device. Concurrently with the initiation of the discharge, an impulsive voltage is impressed upon the delay network for propagation therethrough at a rate determined by the network parameters. A delayed voltage is derived from a predetermined point on the network for impression upon the anode of the discharge device in a polarity to reduce the .anode-to-cathode voltage thereof below the value required to sustain the discharge. The repetition rate of the impulses is determined by the frequency at which the triggering impulses are impressed upon the grid of the discharge device. The time durations or widths of the generated impulse are determined by the delay network parameters.

As is well understood in the art, however, devices of this character are not capable of operating satisfactorily for the generation of impulses at repetition rates greater than adefinite maximum' value. As the repetition rate of the generated impulses is increased it is necessary to decrease the value of the load impedance connected to the anode of the discharge tube in order to obtain impulses of appreciable useful amplitude. Thus, the time constant of the discharging circuit for the delay network is so reduced that the delayed voltage derived from the network does not always remain sufllciently negative for along enough time to eilect the complete deionizaticn of the tube. This situation exists regardless of the widths of the impulses. Additionally, when it is attempted to generate relatively wide impulses at relatively high frequencies by means of prior art generators of this character, it is found that such apparatus is incapable of operating satisfactorily for the reason that there is not sufficient time between 2 successive impulses to enable the tube to deionize completely.

It, therefore, is an object of the present invention to provide a novel impulse generator capable of producing impulses at greater rates of repetition than heretofor have been possible by the use of prior art generators.

Another object of the invention is to provide an impulse generator in which the time durations of the generated impulses are determined by control voltages derived from a delay network and in which there is produced a series of auxiliary control voltages, whereby to insure a more uniform performance of the generator at relatively high repetition rates.

In accordance with the present invention, there is provided a gaseous discharge tube having an anode and a cathode. Means are provided for initiating a discharge in the tube between the anode and the cathode. The discharge is terminated by a plurality of impulsive voltages applied to the tube in a manner to maintain the anode potential suillciently negative with respect to the cathode for a long enough time to effect complete deionization of the tube.

In the twoillustrative embodiments of the invention disclosed herein, there is connected in the output circuit of the gaseous discharge tube a means in which the desired impulses are developed. A series 01' positive impulse developed under the control of the timing apparatus and recurring at'the desired repetition rate of the generated impulses are employed to initiate successive discharges in the tube. A delay network coupled to the anode of the tube is employed to develop one of the deionlzing voltages for the tube. This network is open circuited at its far end so that the voltage which is derived from the tube anode and which is applied to the input terminals 01' the network upon initiation of a discharge in the tube is reflected after reaching the open circuited end of the network for propagation back to the tube anode. Since it is characteristic of this type of network that the reflected voltage is in phase with the impressed voltage, the reflected voltage is applied to the tube in negative polarity to depress the anode-to-cathode voltage sufficiently to start the deionization of the tube.

Also one of a series or positive impulses developed under the control of the timing apparatus is applied through a second delay network to control a means for reversing the polarity of the impulses. In this manner there is developed an auxiliary negative voltage which is coupled to the anode of the gaseous discharge tube to supplement the negative voltage derived from the reflecting delay network. The parameters of the two delay networks are chosen to effect the substantially simultaneous impression of the two differently developed negative voltages upon the anode of the gaseous discharge tube, thereby maintaining the anode-to-cathode voltage depressed for a time sufllcient to eflect the complete d'eionization of the tube.

For a better understanding of the invention, together with other and further objects thereof,

reference is had to the following description,

taken in connection with the accompanying drawing, and its scope will be pointed out in the appended claims.

In the accompanying drawing:

Fig. .i is a circuit diagram, partly schematic, of an impulse generator embodying the present invention;

Fig. 2 is a circuit diagram, partly schematic, of an impulse generator embodying a modification of the invention; and

Fig. 3 is a set of curves illustrative of the mode of operation of an impulse generator embodying the invention.

Having reference now particularly to Fig. 1 of the drawing, there is shown an impulse generator employing a gaseous discharge tube II. Preferably, although not absolutely essential to the successful operation of the device, this tube should be of a type having a shield grid between the control grid and anode and which is maintained at cathode potential. The cathode of this tube is connected to ground through a resistor I2. The terminals of this resistor are connected to the output circuit terminals I3. The anode of the tube 5 I is connected through a relatively low valued load resistor I4 to the positive terminal of a source of direct current such as a battery i5, the negative terminal of which is connected to ground. In high frequency operation, it is necessary to use a load resistor of arelatively low value in order to develop, at the output terminals I3, impulses of appreciable useful amplitude. The anode of the tube II also is connected to one of the input terminals of a delay network I 6. The other input terminal of the network is connected to ground. The details of the network it have not been illustrated for the reason that they may be conventional. The network may be of any well known form such as a two-wire transmission line having a length suitable to produce the desired delay in the propagation of a voltage impressed upon the input terminals thereof. Also, the network may comprise a number of lumped circuit elements such as condensers and inductors arranged in any one of a number of well known configurations. For the particular use which is made in this case of such a network, the other terminals thereof are open circuited so that there is formed what is known as a reflecting type of network.

A series of timing impulses derived from a trigger pulse generator I! is coupled by means of a condenser 48 and a current limiting resistor I9 to the discharge initiating grid of the tube II. This grid is biased suitably with respect to the associated cathode by means of a connection, including a grid leak resistor 2|, to a suitable point on a potentiometer 22. The potentiometer is connected across the terminals of a source of biasing potential such as a battery 23. The battery is poled in a manner to effect a negative biasing of the tube grid with respect to its associated cathode.

The trigger pulse generator I! also is connected to the input terminals of an auxiliary delay net work 24. This network also may be conventional but difi'ers from the network I6 in that its output terminals are connected to an energy absorption resistor 25. The function of this resistor is to absorb completely the energy transmitted through the network so that no reflection occurs. The voltage developed across the resistor 25 is impressed upon the control grid of an electron discharge device 26. This device may be any well known high vacuum tube in which the space current at all times is under the control of the grid of the tube. The other terminal of the resistor 25 is connected to a suitable point on a potentiometer 21 which also is connected across the terminals of the battery 23. This connection is for the purpose of providing a negative biasing voltage for the input circuit of the tube 26 suitable to effect a complete cutoff of space current in the absence of any voltage across the resistor The anode of the tube 26 is connected through a load resistor 28 to the positive terminal of the battery I5. Also, the anode of the tube 25 is coupled by means of a condenser 29 to the anode of the discharge tube II.

Referring now to the operation of the embodiment of the invention disclosed in Fig. 1, assume that tubes II and 26 are non-conducting. In this condition there is no voltage developed across the output resistor I2. A positive impulse from the generator I1 is applied to the grid of the tube I I to initiate a discharge therein. The discharge in the tube I I causes a, current flow through the resistor I2, thereby to develop a voltage which is applied to the output terminals I3. Since the discharge in the tube is substantially instantaneous, the wave front of the voltage developed in the resistor I2 is sufliciently steep to be regarded as vertical with respect to a horizontal time base.

Also, there is a current flow initiated in the resistor I4 which causes a, substantially instantaneous decrease of the positive anode voltage of the tube with respect to ground. Such a decrease is the equivalent of impressing a negative voltage upon the input terminals of the delay network I6. This voltage is propagated through the network to its far end from which it is reflected for propagation back to its input terminals. Since the reflected voltage is in phase with the impressed voltage, it renders the anode potential of the tube I I negative with respect to the cathode. The depression of the anode-to-cathode voltage of the tube I I into the negative region starts the deionization of the tube. However, in high frequency operation, the reflected voltage does not always remain sumciently negative for a long enough time to effect complete deionization. This condition results from the necessity of using a relatively low valued resistor as the load resistor I4. Thus, the discharge of the capacitance of the network I6 through this resistor occurs with sufilcient rapidity to prevent the anode potential of the tube II from remaining below the discharge sustaining potential long enough to eiIect complete deionization of the tube.

The positive trigger impulse from the generator IT, at the time it is applied to the grid of the tube II, also is impressed upon the input terminals oi the delay network 24. The parameters of this network are chosen to eifect a delay in the propagation of the impressed voltage which is slightly in excess of the total time required for the voltage impressed upon the delay network IE to traverse this latter network twice. Consequenrtly, when the trigger impulse has completely traversed the network 24 to initiate the conduction of space current in the tube 26, the negative 1 voltage reflected by the delay network I 3 isimpressed upon the anode of the tube II.

Byreason of the inherent phase inversion characteristic of a vacuum tube, an auxiliary negative voltage is developed at the anode of the tube 26 in response tothe positive impulsive voltage impressed upon the grid of this tube. This negative voltage is applied to the anode of the tube II to produce an additional depression of the anode-to-cathode voltage of the gaseous discharge tube. The combination of these two negative voltages is suflicient to maintain the depresalso is decreased to zero substantially instantaneously.

Referring now to Fig. 2 of the drawing, the modification of the inventtion illustrated therein will be described. Insofar as the apparatus of this figure corresponds with that of Fig. l, the same characters of reference are used to designate such apparatus. In this form of the invention the timing impulses which'are impressed upon the input circuit of the electron discharge device 26 are derived from an output circuit impedance device 3| connected to the cathode of the gaseous discharge tube II. Thisv impedance device is in the form of a potentiometer, the movable element 32 of which is connected to the input terminals of the non-reflecting delay network 24.

The terminating resistor 25 for the network 24 is connected to the input circuit of tube 26. The cathode of this tube is connected to ground through a self-biasing resistor 33 with which there is connected in parallel a lay-pass condenser 34.

The cathode of this tube also is connected through.

a resistor 35 of relatively high value to the positive terminal of the battery I5. In this manner the input circuit of the tube 26 is provided with 'an additional biasing voltage to insure a complete cutoff of space current .at times when there is no voltage developed in the resistor 25. Space current for the tube 26 is provided from the battery I5 by means of a connection which includes a resistor 36. The anode of the vacuum tube 26 and the anode of the discharge tube I I are interconnected by a resistor 31.

Referring now to the operation of the embodiment of the invention illustrated in Fig. 2, assume that both tubes II and 26 are non-conducting. A positive impulse from the generator II, when impressed up n. the discharge initiating grid of the tube I, causes a discharge between the anode and cathode of the tube. characteristically, this discharge occurs substantially instantaneously so that there is' developed in the output resistor 3| a voltage having an extremely steep wave front. The current flow through resistors 33 and 31 effects a. voltage drop across the resistors, whereby the anode voltage of the tube II is reduced. As in the previous instance, the reduction of the positive anode voltage of the tube II resulting from the discharge in the tube causes the impression upon the delay network It of a negative Voltage which ultimately is reflected from the far end of the network and is applied as a deionizing voltage to the tube II.

While this is occurring, 9. portion of the steep wave front voltage, developed in the resistor 3| is impressed upon the non-reflecting delay network 24. At substantially the same time that the negative voltage reflected by the network I6 is impressed upon the anode of the tube I I, the J This space current effects a, greater voltage drop in the resistor 36 whereby to effect a decrease of the voltage at. the junction point of resistors 36 and 31. Consequently, a still more negative voltage is. impressed through resistor 31 upon the anode of the discharge tube II. This auxiliary negative voltage, together with the voltage reflected from the network I6, is sumcient to effect complete deionizatiorrof the tube I I.

It will be noted that a somewhat improved performance of the embodiment of Fig. 2 may be obtained by reason of the better wave form of the impulses employed to control the development of the auxiliary deionizing voltage. While suitable for most purposes, the wave shape of timing impulses derived from conventional multivibrators are not always sufllciently steep to control the development of satisfactory deionizing voltages for apparatus of this character, when the impulse repetition rates are extremely high. The output circuit of the gaseous discharge tube |I provides a convenient source of steep wave front impulses. Consequently, by deriving the deionizing voltage control impulses from this circuit a more satisfactory operation of the apparatus is obtained when operating under the extreme conditions specified.

Reference to Fig. 3, wherein there are illustrated graphically the anode-to-cathode voltage variations of the tube II in relation to the generated impulses, will serve to more clearly emphasize the novel mode of operation of the described apparatus embodying the instant inven,

tion. This portion of the description will be given specifically with reference to Fig. 1, it being understood that it applies equally well to the apparatus of Fig. 2. With both tubes I I and 26 in nonconducting states the anode voltage of tube II is at its highest positive value with respect to the cathode of this tube. This condition is illustrated in Fig, 3 by the horizontal line 38. As

. soon as a discharge is initiated in the tube II the Ill) - the horizontal line 4|.

When the negative voltage, which is reflected by the network I6, is impressed upon the anode of the tube II, the anode-to-cathode voltage of the tube is-depres sed abruptly into the negative region. This voltage depression i illustrated by the vertical line 42. Concurrently withthe' depression of the anode-to-cathode voltage of the tube II the discharge in the tube is terminated and the deionization process is started. Thus, the resulting abrupt interruption of the current flow through the output resistor I2 effects a corresponding abrupt decrease to zero in the voltage developed therein which is represented by the horizontal line 43. This condition is maintained until another discharge is initiated in the tube I I.

Immediately following the depression of the anode-to-cathode voltage of the tube II as illustrated by the line 42 the negative voltage derived Concurrently with the.

spam

from the network i6 begins to decay exponentially as represented by the line 44. This voltage decay occurs at a. relatively rapid rate for the reason that the load resistor H has the relatively low value necessary for operation at a relatively high repetition rate. The anodetocathode voltage of the tube ll, therefore, would not be maintained sufficiently negative for a long enough time to permit complete deionization of the tube.

However, before the anode-to-cathode voltage of tube II can decay to the value necessary to again initiate a discharge in the tube, the nega-' tive voltage derived from the tube 26 is impressed upon the anode otthe tube ii. This negative voltage is represented by the vertical line 45. It is seen that the application of this voltage at this time prevents the anode-to-cathode voltage of tube I i from reaching the value necessary to initiate a second discharge in the tube. Immediately, however, the anode-to-cathode voltage of the discharge tube again begins its exponential decay as represented by the line 46. By the time that the anode-to-cathode voltage represented by this line reaches a value suillcient to initiate a discharge in the tube, complete deionization will have been eifected so that a second discharge may be initiated only under the control of the grid of the tube. Consequently, the anode-to-cathode voltage continues to rise to the maximum positive value represented by the horizontal line 41. The described cycle of operation then is repeated.

While it will b understood that the circuit specifications of the two forms of impulse generators disclosed herein may vary according to the particular service requirements, the following specifications for generators capable of producing impulse having time durations as little as 0.25 microsecond at repetition rates up to a maximum of 3600 impulses per second, are included,

by way of example only:

Tube ii 2050 Resistor i2 ohms 70' Resistors I4, 28 and 36 do 10,000 Battery i5 volts..- 300 Condenser l8 microfarad's 0.01 Resistor i9 ohms 100,000 Resistor 2i -do 270,000 Potentiometers 22 and 2'| megohm 1 Battery 23 volts 45 Resistor 25 ohms 1,000 Tube 26 6V6GT Condenser '29 microfarads 0.1 Potentiomcter 3| oh.ms 70 Resistor 33 do 500 Condenser 34 microfarads 10 Resistor 35 ohms 500,000 Resistor 31 do 5,000

While there has been described what, at present, is.considered the preferred embodiment of the invention, it will be obvious to those skilled in th art that various changes and modifications of each oi said generatedimpulses, an electron discharge device, an input circuit for said electron discharge device including a non-reflecting" type of delay network, said non-reflecting delay "network having propagation rate equal subgaseous discharge tube an extinguishing voltage,

a source of triggering impulses, and means for impressing impulses developed under the control of said impulse source substantially concurrently upon the input circuit of said gaseous discharge tube and upon said non-reflecting delay network.

2. An impulse generator comprising, a gaseous discharge tube having an anode, a cathode, and discharge initiating grid, a circuit connected to said cathode for the development therein oi the generated impulses, a reflecting type of delay network having a propagation time substantially equal to one-half of the time duration of each of said generated impulses, means for coupling said reflected network to the anode of said discharge tube in a manner to efl'ect the impression of a negative voltage upon said network concurrently with th initiation of a discharge in said tube, an electron discharge device having an anode and a control grid, means for coupling the anode of said electron discharge device to the anode of said discharge tube for the impression thereon of a negative voltage supplementary to the negative reflected voltage derived from said reflecting network, a non-reflecting type of delay network having one of two terminals coupled to the control grid of said electron discharg device, impulse timing apparatus, and means for impressing impulses of positive polarity developed under the control of said timing apparatus concurrently upon the discharge initiating grid of said discharge tube and upon the other terminal of said non-reflecting delay network.

3. An impulse generator comprising, a gaseous discharge tube, means including a positive impulse source to initiate a discharge in said tube, means controlled by said tube discharge for developing a first negative voltage, means for reversing the polarity of a positive impulse derived from said source to develop a second negative voltage, and means including a delay network for impressing substantially simultaneously said negative voltages upon said tube after the lapse of a predetermined time in a manner to effect deionization of said tube.

4. An impulse generator comprising, a gaseous discharge tube, means including a positive impulse source to initiate a discharge in said tube, means coupled to said tube and controlled by said discharge therein for developing a first negative voltage, means for amplifying and reversing the polarity of a positive impulse derived from said source to develop a second negative voltage, and means including a delay network for impressing substantially simultaneously said negative voltages upon said tube after the lapse of a predetermined time in a manner to effect deionization of said tube.

5. An impulse generator comprising, a gaseous discharge tube, means including a positive impulse source to initiate a discharge in said tube, means including a first delay network controlled by said discharge to impress a negative voltage upon said tube after the lapse of a predetermined time in a manner tending to deionize said tube, means for reversing the polarity of a including a second delay network for impressing said auxiliary negative voltage upon said tube in a manner tending to deionize said tube and substantially contemporaneously with said first named negative voltage, whereby to effect complete-deionization of said tube.

6. An impulse generator comprising, a gaseous discharge tube, means including a positive impulse source to initiate a discharge in said tube, means including a reflecting delay network controlled by said discharge to impress a negative voltage upon said tube after the lapse of a predetermined time in a manner tending to deionize said tube, means for amplifying and reversing the polarity of a positive impulse derived from said source to develop an auxiliary negative voltage, and means including a non-reflecting delay network for impressing said auxiliary negative voltage upon said tube in a manner tending to deionize said tube and substantially contemporaneously with said first named negative voltage, whereby to efi'ect complete deionization of said tube. i

7. An impulse generator comprising, a gaseous discharge tube having an input circuit and an output circuit, a reflecting delay network coupled to said output circuit, a source of triggering impulses coupled to said input circuit to initiate a discharge in said tube whereby to impress upon said reflecting network an impulsive voltage, said impulsive voltage being reflected from said network after a predetermined time delay to develop in the output circuit of said discharge tube an additional voltage of a polarity tending to deionize said tube, an electron discharge device having an input circuit and an output circuit, a nonreflecting delay network coupled between said source of triggering impulses and the input circuit of said electron discharge device and adapted to impress said triggering impulses upon the input circuit of said device after a delay of slightly more than said predetermined time delay, means included in the output circuit of said electron discharge device for developing an auxiliary impulsive voltage of a polarity tending to deionize said discharge tube, and means for impressing said auxiliary impulsive voltage upon theoutput circuit of said discharge tube substantially contemporaneously with the reflected impulsive voltage derived from said first delay network, whereby to effect complete deionization of said gaseous discharge tube.

8. An impulse generator comprising, a gaseous discharge tube having an input circuit and an output circuit, said output circuit including means for the development therein 01' saidgenerated impulses, a reflecting delay network coupled to said output circuit, a source of triggering impulses coupled to said input circuit to ini tiate a discharge in said tube whereby to impress upon said reflecting network a negative voltage. said negative voltage being reflected from said network after a predetermined time delay to develop in the output circuit of said dischargetube an additional negative voltage tending to deionize said tube, an electron discharge device having an input circuit and an output circuit, a non-reflecting delay network coupled between said source of triggering impulses and the input circuit of said electron discharge device and adapted to propagate said triggering impulses at a rate slightly less than one-half of the propagation rate or said reflecting delay network,

means including said electron discharge device for developing in the output circuit thereof an auxiliary negative voltage, and means for impressing said auxiliary voltage upon the output circuit of said discharge tube substantially contemporaneously with the reflected negative voltage derived from said first delay network, whereby to effect complete deionization of said gaseous discharge tube.

9. An impulse generator comprising, a gaseous discharge tube having an anode, a cathode and a discharge initiating grid, an impedance-connected to said cathode for the development therein of said generated impulses, a delay networkhaving one end thereof connected to said anode and the other end thereof open circuited, a source of triggering impulses coupled to said grid to initiate a discharge in said tube whereby to impress upon said network a negative voltage, said negative voltage being propagated through said network and reflected from the open circuited end thereof to develop at theanodeof said discharge tube an additional negative voltage tending to deionize said tube, an electron discharge device having input and output circuit electrodes, a second delay network coupled between said source of triggering impulses and the input circuit electrodes of said electron discharge device and adapted to propagate, said triggering impulses at a rate slightly less than one-half of the propagation rate of said first delay network, means including said electron discharge device for developing at the output circuit electrodes of said device an auxiliary negative voltage, and a coupling between the output circuit electrodes of said electron discharge device and the anode of said gaseous discharge tube for impressing said auxiliary voltage upon said gaseous discharge tube substantially contemporaneously with the reflected negative voltage derived from said first delay network, whereby to insure complete deionization of said gaseous discharge tube.

10. An impulse generator comprising, a gaseous discharge tube having an anode, a-cathode and a discharge initiating grid, an impedance connected to said cathode for the development therein of said generated impulses, asource of direct current and an impedance connected to said anode, a delay network having one end thereof connected to said anode and the other end thereof open circuited, a source of triggering impulses coupled to said grid to initiate a. discharge in said tube whereby to impress upon said delay network a negative voltage, said negative voltagebeing propagated through said network and reflected from'the open circuited end thereof to develop at the anode of said gaseous dis-,

charge tube'an additional negative voltage'tend- I ing to deionize said tube, an electron discharge device having inputand output circuit electrodes, a second delay network having an energy absorption terminating impedance, said second delay network being coupled between said source of triggering impulses and the input circuit electrodes of said electron discharge device and being adapted to propagate said triggering impulses at a rate slightly less than one-half of the propagation rate of said first delay network, means controlled by the input circuit electrodes of said electron discharge device for developing at the output circuit electrodes of said device an auxiliary negative voltage, and a coupling between the output circuit electrodes of said electron discharge device and the anode of said gaseous discharge tube for impressing said 11 auxiliary voltage upon said gaseous discharge tube substantially contemporaneously with the reflected negative voltage derived from said first delay network, whereby to insure complete deionization of said gaseous discharge tube.

11. An impulse generator comprising, a gaseous discharge tube having an output circuit in which to develop said generated impulses, means including a positive impulse source to initiate a discharge in said tube, means controlled y said discharge to impress a. negative voltage upon said tube after the lapse of a predetermined time in a manner tending to deionize said tube, means including an amplifier for converting one of said generated impulses into an auxiliary negative voltage, and means for impressing said auxiliary negative voltage upon said tube in a manner tending to deionize said tube and substantially contemporaneously with said first named negative voltage, whereby to eiiect complete deionization of said tube.

12. An impulse generator comprising, a gaseous discharge tube having an input circuit and an output circuit, means in said output circuit for the development therein oi the generated impulses, a reflecting t pe of delay network associated with said output circuit, said reflecting delay network having a propagation time substantially equal to one-half of the time duration of each of said generated impulses, a source or triggering impulses coupled to said input circuit to initiate a discharge in said tube, means in said output circuit for impressing a negative voltage upon said reflecting delay network concurrently with the initiation of the discharge in said tube, an electron discharge device having an input circuit and an output circuit, said output circuit being coupled to the output circuit of said gaseous discharge tube, a non-reflecting type of delay network coupled between the input circuit oi, said electron discharge device and charge device and the cathode circuit of said gaseous discharge tube-said non-reflecting network having a propagation rate equal substantially to one-half of the propagation rate 01 said reflecting network, and means including said electron discharge device for developing an auxiliary negative voltage for impression upon the anode of said gaseous discharge tube substantially contemporaneously with the impression thereon of the reflected negative voltage developed by said reflecting delay network.

- 14. An impulse generator comprising, a gaseous discharge tube having an anode, a cathode and a discharge initiating grid, an impedance device connected to said cathode for the development therein oi saidgenerated impulses, a reflecting type of delay network connected to said anode, said reflecting delay network having a propagation time substantially equal to one-half of the time duration oi each of said generated impulses, a source of triggering impulses coupled to said grid to initiate a discharge in said tube, means including a current source connected to said anode for impressing a negative voltage upon said reflecting delay network concurrently with the initiation of the discharge in said tube, an electron discharge device having an anode and a control grid, said anode being coupled to the anode of said gaseous discharge device, a non-reflecting type of delay network coupled between the control grid of .said electron discharge device and the cathode impedance device of said gaseous discharge tube, said non-reflecting network having a propagation rate equal substantially to one-half or the propagation rate of said reflecting network, and means including said non-reflecting network to initiate the conduction of space current in said electron discharge device for developing an am:-

iliar negative voltage for impression upon the the impulse developing means in the output cireous discharge tube having an anode, a cathode and a discharge initiating grid, a, circuit connected to said cathode for the development therein of the generated impulses, a reflecting type of delay network associated with a circuit connected to said anode, said reflecting delay network having a propagation time substantially equal to one-half of the time duration of each of said generated impulses, a source of triggering impulses coupled to said grid to initiate a discharge in said tube, means included in said anode circuit for impressing a negative voltage upon said reflecting delay network concurrently with the initiation of the discharge in said tube, an electron discharge device having an anode and a control grid,'said anode being coupled to the anode circuit of said gaseous discharge tube, a non-reflecting type of delay network coupled between the control grid of said electron disanode of said gaseous discharge tube substantially contemporaneously with the impression thereon of the reflected negative voltage developed by said reflecting delay network.

15. An impulse generator comprising, a gaseous discharge tube having an anode and a cathode, means including a triggering impulse source for initiating a discharge in said tube, means including a first delay network responsive to said tube discharge to develop a negative impulsive voltage, means including a second delay network responsive to an impulse developed under the control of said triggering impulse source to develop another negative impulse voltage, and means for impressing said negative impulsive voltages substantially concurrently between said anode and said cathode to effect complete deionization 01' said tube.

JOSEPH D. SCHANTZ.

REFERENCES CITED The following references are of record in the flle of this patent:

UNITED STATES PATENTS Number Name Date 2,212,967 White Aug. 27, 1940 2,212,173 Wheeler et a1. Aug. 20, 1940 2,293,570 Stibitz Aug. 18, 1942 2,212,420 Harriett Aug. 20, 1940 2,255,839 Wilson Sept. 16, 1941 2,266,154 Blumlein Dec. 16, 1941 2,188,970 Wilson Feb. 6, 1940 

